1. Field of the Invention
The present invention relates generally to thin film transistors. The present invention relates more specifically to a thin film transistor substrate on which a thin film transistor having improved characteristics is arranged, a display apparatus having the thin film transistor substrate, and a method of manufacturing the thin film transistor substrate.
2. Description of the Related Art
In general, a thin film transistor substrate includes at least one thin film transistor (TFT) formed thereon. The TFT switches signals that are transmitted through wires arranged on the substrate.
The TFT typically includes a gate electrode, a source electrode, a drain electrode, and a semiconductor pattern that defines a channel area. Also, the TFT typically includes an etch stop layer that is arranged on the semiconductor pattern. The etch stop layer prevents the semiconductor pattern from being over-etched when other layers are formed on the semiconductor pattern.
However, if the etch stop layer is formed on the semiconductor pattern by a photolithography process after the semiconductor pattern is formed, the semiconductor pattern commonly becomes over-etched. Thus, when the etch stop layer is formed, a material having a higher etch selectivity than that of the semiconductor pattern is often desirable for the etch stop layer.